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RE: [RFC PATCH 01/35] merge: improve fatal fast-forward message

From
Felipe Contreras <felipe.contreras@gmail.com>
Date
Jul 6, 2021, 21:11 UTC
Message-ID
<60e4c71099ef_1c4281208ad@natae.notmuch>
In-Reply-To
<04de01d772a8$540c6690$fc2533b0$@nexbridge.com>
Randall S. Becker wrote:
Show 47 quoted lines
> On July 6, 2021 4:40 PM, Felipe Contreras wrote:
> >Subject: Re: [RFC PATCH 01/35] merge: improve fatal fast-forward message
> >
> >Ævar Arnfjörð Bjarmason wrote:
> >>
> >> On Mon, Jul 05 2021, Felipe Contreras wrote:
> >>
> >> > Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
> >> > ---
> >> >  builtin/merge.c | 2 +-
> >> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >> >
> >> > diff --git a/builtin/merge.c b/builtin/merge.c index
> >> > a8a843b1f5..05e631229d 100644
> >> > --- a/builtin/merge.c
> >> > +++ b/builtin/merge.c
> >> > @@ -1620,7 +1620,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
> >> >  	}
> >> >
> >> >  	if (fast_forward == FF_ONLY)
> >> > -		die(_("Not possible to fast-forward, aborting."));
> >> > +		die(_("unable to fast-forward"));
> >>
> >> I read the existing message a bit more like "this makes no sense
> >> anymore" (correct) and the latter more like "we encountered an error".
> >
> >I mean, this is the documentation of --ff-only:
> >
> >  With `--ff-only`, resolve the merge as a fast-forward when possible.
> >  When not possible, refuse to merge and exit with a non-zero status.
> >
> >So if you do `git merge --ff-only` you are telling git: "I want you to exit with an error when the fast-forward is not possible".
> >
> >If you do:
> >
> >  % git merge --ff-only
> >  fatal: Not possible to fast-forward, aborting.
> >
> >That "aborting" part is redundant; we know `git merge` should abort if the fast-forward is not possible, we explicitely told git to do that.
> 
> `git merge` is a special operation where errors (conflicts, for one)
> may leave the repository in a merge pending state where you
> subsequently may have to use `git merge --abort` to reset the
> situation or `git add` to continue. The `aborting` output makes it
> clear that you do not have to do the `--abort` and *cannot* do the
> `add` because there was an implicit `--abort` done resulting from the
> failure.

But this is not a `git merge`, this is a `git merge --ff-only`; they are different operations. There *never* is a need for `--abort` with `git merge --ff-only`.

Anyway, the error message is meant for `git fast-forward` which definitely doesn't need any `--abort`.

Initially I created a new variable to have a different error message for `git merge --ff-only` and `git fast-forward`, precisely to avoid changing the current error message of `git merge --ff-only` and thus avoid any inertial comments like this one. But then I thought there was no need to complicate the series when both can be improved at once. Apparently that's not the case.

I guess I'll add it back.
Cheers.
-- 
Felipe Contreras
Previous: Randall S. BeckerNext: Randall S. Becker
Message 11 of 53 in “git update: fix broken git pull”
  1. 00/35 git update: fix broken git pullFelipe Contreras, Jul 5, 2021
  2. 01/35 merge: improve fatal fast-forward messageFelipe Contreras, Jul 5, 2021
  3. Ævar Arnfjörð BjarmasonJul 6, 2021
  4. Felipe ContrerasJul 6, 2021
  5. Randall S. BeckerJul 6, 2021
  6. Junio C HamanoJul 6, 2021
  7. Felipe ContrerasJul 6, 2021
  8. Randall S. BeckerJul 6, 2021
  9. Junio C HamanoJul 6, 2021
  10. Randall S. BeckerJul 6, 2021
  11. Felipe ContrerasJul 6, 2021
  12. Randall S. BeckerJul 6, 2021
  13. Felipe ContrerasJul 6, 2021
  14. 02/35 merge: split cmd_merge()Felipe Contreras, Jul 5, 2021
  15. 03/35 fast-forward: add new builtinFelipe Contreras, Jul 5, 2021
  16. 04/35 doc: fast-forward: explain what it isFelipe Contreras, Jul 5, 2021
  17. 05/35 fast-forward: add advice for novicesFelipe Contreras, Jul 5, 2021
  18. Ævar Arnfjörð BjarmasonJul 6, 2021
  19. Felipe ContrerasJul 6, 2021
  20. 06/35 fast-forward: make the advise configurableFelipe Contreras, Jul 5, 2021
  21. 07/35 fast-forward: add help about merge vs. rebaseFelipe Contreras, Jul 5, 2021
  22. 08/35 update: new built-inFelipe Contreras, Jul 5, 2021
  23. 09/35 update: add options and usage skeletonFelipe Contreras, Jul 5, 2021
  24. 10/35 update: add --ff optionFelipe Contreras, Jul 5, 2021
  25. Ævar Arnfjörð BjarmasonJul 6, 2021
  26. Felipe ContrerasJul 6, 2021
  27. 11/35 update: add --merge modeFelipe Contreras, Jul 5, 2021
  28. Ævar Arnfjörð BjarmasonJul 6, 2021
  29. Felipe ContrerasJul 6, 2021
  30. 12/35 commit: support for multiple MERGE_MODEFelipe Contreras, Jul 5, 2021
  31. 13/35 merge: add --reverse-parents optionFelipe Contreras, Jul 5, 2021
  32. 14/35 update: reverse the order of parentsFelipe Contreras, Jul 5, 2021
  33. 15/35 update: fake a reverse order of parents in messageFelipe Contreras, Jul 5, 2021
  34. 16/35 update: add --rebase modeFelipe Contreras, Jul 5, 2021
  35. 17/35 update: add mode configuationFelipe Contreras, Jul 5, 2021
  36. 18/35 update: add per-branch mode configurationFelipe Contreras, Jul 5, 2021
  37. 19/35 pull: cleanup autostash checkFelipe Contreras, Jul 5, 2021
  38. 20/35 pull: trivial cleanupFelipe Contreras, Jul 5, 2021
  39. 21/35 pull: trivial whitespace style fixFelipe Contreras, Jul 5, 2021
  40. 22/35 pull: introduce --merge optionFelipe Contreras, Jul 5, 2021
  41. 23/35 rebase: add REBASE_DEFAULTFelipe Contreras, Jul 5, 2021
  42. 24/35 pull: move configuration fetchesFelipe Contreras, Jul 5, 2021
  43. 25/35 pull: show warning with --ff optionsFelipe Contreras, Jul 5, 2021
  44. 26/35 pull: add pull.modeFelipe Contreras, Jul 5, 2021
  45. 27/35 pull: add per-branch mode configurationFelipe Contreras, Jul 5, 2021
  46. 28/35 pull: add pull.mode=fast-forwardFelipe Contreras, Jul 5, 2021
  47. 29/35 pull: reorganize mode conditionalsFelipe Contreras, Jul 5, 2021
  48. 30/35 pull: add diverging advice on fast-forward modeFelipe Contreras, Jul 5, 2021
  49. 31/35 pull: improve --rebase and pull.rebase interactionFelipe Contreras, Jul 5, 2021
  50. 32/35 pull: improve default warningFelipe Contreras, Jul 5, 2021
  51. 33/35 pull: advice of future changesFelipe Contreras, Jul 5, 2021
  52. 34/35 FUTURE: pull: enable ff-only mode by defaultFelipe Contreras, Jul 5, 2021
  53. 35/35 !fixup FUTURE: pull: enable ff-only mode by defaultFelipe Contreras, Jul 5, 2021

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